mc68hc908lj24 Freescale Semiconductor, Inc, mc68hc908lj24 Datasheet - Page 229

• Manufacturer Part Number: mc68hc908lj24
• Description: M68hc08 Microcontrollers
• Manufacturer: Freescale Semiconductor, Inc

12.9 Low-Power Modes
12.9.1 Wait Mode
MC68HC908LJ24/LK24 — Rev. 2.1
Freescale Semiconductor
RTCWE_R EQU
...
RTC_WRTIE_PROTECT
...
To disable write-protect after write-protect is enabled execute the
following code:
RTCWE1 EQU
RTCWE0 EQU
RTCWE_R EQU
...
RTC_WRITE_ENABLE
...
...
; Write-protect is disabled, RTC registers/bits can be written.
...
; Protect register/bits again after write access.
RTC_WRTIE_PROTECT
...
The STOP and WAIT instructions put the MCU in low power-
consumption standby modes.
The RTC module continues normal operation in wait mode. Any enabled
CPU interrupt request from the RTC can bring the MCU out of wait
mode. If the RTC is not required to bring the MCU out of wait mode,
power down the RTC by clearing the RTCE bit before executing the
WAIT instruction.
Real Time Clock (RTC)
$40
1
0
$40
;RTCCOMR register
BSET
BSET
;RTCWE1 bit
;RTCWE0 bit
;RTCCOMR register
BSET
BSET
BCLR
BSET
LDA
ORA
STA
BSET
BSET
BSET
RTCWE1,RTCWE_R ;write %10
RTCWE1,RTCWE_R ;write %10 again
RTCWE1,RTCWE_R ;write %10 twice to
RTCWE1,RTCWE_R ;ensure protected
RTCWE1,RTCWE_R ;write %00
RTCWE0,RTCWE_R ;write %01
RTCWE_R
#%00000011
RTCWE_R
RTCWE1,RTCWE_R ;write %10
RTCWE1,RTCWE_R ;write %10
RTCWE1,RTCWE_R ;write %10 again
;write %11
Real Time Clock (RTC)
Low-Power Modes
Data Sheet
229